This application is based upon and claims the priority of Japanese Patent Application No. 2001-072806, filed on Mar. 14, 2001, which is hereby incorporated by reference in its entirety.
1. Field of the Invention
The present invention generally relates to an improved engine for land vehicles. More specifically, the present invention relates to an improved lubrication system layout for an engine that results in a generally smaller engine, and thus a generally smaller vehicle body.
2. Description of the Related Art
Snowmobiles are powered by internal combustion engines that are mounted within a substantially enclosed engine compartment forward of the rider""s seat. The engine compartment typically is defined within a cowling and is generally relatively small.
Internal combustion engines generally have a lubrication system to reduce friction between moving components, which causes heat and wear of the moving components of the engine. The lubrication system sometimes includes a lubricant pump for supplying lubricant to the various moving components, a lubricant cooler for removing heat from the lubricant, and a lubricant filter for removing debris from the lubricant. Typically, the lubricant pump is mounted on the opposite side of the engine from the lubricant cooler and the lubricant filter.
Positioning the lubricant filter and the lubricant cooler on the opposite side of the engine from the lubricant pump is disadvantageous for snowmobile applications because it increases the distance between these components, which increases the size of the engine. Also, a more complex system of conduits is required to route the lubricant to these components and to the moving engine components.
Thus, an engine layout that can reduce the engine size and reduce the complexity of the lubrication system is desired.
Accordingly, one aspect of the present invention involves a snowmobile that has a frame assembly that defines a longitudinal vertical plane and a transverse vertical plane. An internal combustion engine is mounted to the frame assembly generally along the transverse vertical plane of the frame assembly. The internal combustion engine includes a cylinder block that defines a cylinder bore and a crankcase connected to the cylinder block. The crankcase defines a crankcase chamber. The crankcase has a crankshaft journaled therein that rotates about a crankshaft axis. The engine also has a piston reciprocally positioned in the cylinder bore that drives the crankshaft. The engine also has a lubrication system that includes a lubricant pump unit mounted in the crankcase chamber, a lubricant cooler, and a lubricant filter. The lubricant pump unit is mounted at a location offset from the crankshaft axis. The lubricant pump unit also has a lubricant pump that is rotatable about a lubricant pump axis. At least one of the lubricant cooler and the lubricant filter is positioned on the same side of the engine as the lubricant pump unit.
Another aspect of the present invention involves an internal combustion engine that includes a crankcase and a cylinder block that defines a cylinder bore. The crankcase is connected to the cylinder block and defines a crankcase chamber. A crankshaft is journaled in the crankcase and is rotatable about a crankshaft axis. A piston that is reciprocally positioned in the cylinder bore drives the crankshaft. The engine also has a lubrication system that includes a lubricant cooler, a lubricant filter, and a lubricant pump unit. The lubricant pump unit is mounted in the crankcase chamber at a location offset from the crankshaft axis. The lubricant pump unit includes a lubricant pump that is rotatable about a lubricant pump axis. At least one of the lubricant cooler and the lubricant filter is positioned on the same side of the engine as the lubricant pump unit.